1. Field of the Invention
The field of the invention is that of aircraft flight plan displays or air traffic control station displays. It more generally concerns the devices and methods for displaying navigation plans for all types of craft (airborne, seaborne, terrestrial and spaceborne).
2. Description of the Related Art
It will be recalled that an aircraft is equipped with a navigation aid system called FMS, an acronym that stands for Flight Management System. The latter communicates with other external systems and systems on board the aircraft. The navigating crew communicates with the FMS via human-machine interfaces (HMI) having viewing screens and means of controlling and pointing to elements displayed on the viewing screen. The navigation aid system assists the crew in programming the flight plan before take-off and in following the flight plan, from take-off to landing. Its displays, on one of the viewing screens that form the cockpit, the flight plan of the aeroplane. This screen is called “navigation display”. More and more systems make it possible to make forecasts. Such is the case, for example, of the weather radar in an aeroplane cockpit or of the aeroplane flight path computer in a control station or an air traffic control station. Weather radars are these days capable of supplying information in real time to the FMS concerning the intensity or the location of bad weather facing the aeroplane. More generally, the different forecasting computers have the capability to give information concerning the external environment likely to interfere with the navigation plan of the craft. Furthermore, it is possible with these different computers to display, for example, future data concerning the surrounding air traffic, the weather and zones for changing communication frequency that occur along the flight plan. In order to facilitate understanding the future situation, the latter must be displayed in the same format as the current situation. This prerequisite therefore requires a display co-located on the “Navigation Display”. Unfortunately, this display can induce human errors if the user interprets the future situation as being the current situation. For example, in the case of the display of the future air traffic, the user may understand that another aircraft is close to collision whereas the latter will reach that position only sometime later. The major issue is to find a display method that avoids any possibility of wrongly interpreting the forecasts and renders the presentation of the information as clear as possible.
Systems are known, as described in patent WO-A1-2005101055, that use, for example, weather forecasting computers coupled to the flight plan computer of an aeroplane. This system performs calculations to correlate the flight plan with weather forecasts and issues alarms in case of serious dangers. This system only performs calculations and initiates alarms. Now, the new forecasting systems can offer the pilots more forecasting services, to display the changing flight plan. It is a good thing, for example, for a pilot to be able to view the changes to the external environment in the vicinity of his flight plan and, above all, in addition, for all the data to be accessible by the databases and the various computers on board the aeroplane. To exploit the forecasting computers, it is essential to put in place a display method that makes it possible to use its forecasting data. It is mandatory for this method to facilitate the interpretation of the data without risk of ambiguity with the data of a current situation.